Lifting jack



. B. BOSTWICK.

LIFTING JACK.

APPLlcAloN FILED :une 2x5, 1920.

m mmm @ma 31,1922,

f Arron/vers.

Patented Unt. 3l, l922.

Jil-a9 i JAMES 1B. EOSTWICK, 0E JERSEY CITY, NEW JERSEY.

MEETING- JACK.

T o aZZ whom t may con-cern.' Y

Be it known-that l, JAMES B. Bos'rwion, a citizen of the United States,and a resident of Jersey City, in the county ofr Hudson and State of`1New Jersey, have invented new and useful lmprovements in LiftingJacks, of which the following is a specification.

The invention relates vin general to lifting jacks, and more articularlyto lifting jacks operated by fluid pressure.

rlfhe objects of the invention are to provide a. combined fluid pressureoperated jack and fluid reservoir embodying novel features ofconstruction; to provide such a lifting jack havin a hollow piston ofnovel construction w ich serves as a reservoir for the fluid underpressure; to obtain a novel construction and arrangement of passages andconnections for first charging the reservoir directly with fluid underpressure, subsequently releasing a portion of the fluid from thereservoir behind the piston to elevate the same when it is desiredtoutlize the jack for lifting purposes, and after such use releasing thefluid pressure from behind the piston into the atmosphere to allow thepiston to resume its normal position; to provide ay novel valve meansfor so charging the reservoir and transferring the fluid therefrom, andto obtain other advantages and .results as may be brought out by thefollowing description. l l

Feferrin to t-he accompanying drawings, in which like numerals ofreference indicate the same parts throughout the several views,

Figure l is a vertical longitudinal sectional view through a liftingjack embodying my invention. taken on the line 1-1 of Fig. ll, andshowing the piston of the jack in its normal inoperative position;

Figure 2 is a sectional view through the cylinder of the jack, thepiston and valve nipple being shown in side elevation andthe pistonbeing shown in an operative position;

Figure 3 1s a top plan view of the j ack;

Figure 4t is an enlarged fragmentary sectional view taken on theline4:-4 of Fig. l,

and

Figure 5 is a detail view of the j ack head and an extension therefor.

ln the specific embodiment of the invention-illustrated by the drawings,the numeral l designates the lcylinder of the jack which may beconstructed of any suitable material such as steel, brass or the like,and which may be formed in any suitable manner as by casting, stampingor machining according to the size of jack desired and the purpose forwhich the jack is desired. ln the present instance my invention-has beenshown embodied in a vehicle jack, and the cylinder l is shown as havingone end thereof open and being substantially elliptical in crosssectionfor the purpose of providing an enlarged area for the base of the jackand also for preventing rolling of the jack when the same is laid uponits side. This elliptical formation of the cylinder also preventsrotation or twistin of a similarly formed pis- 7o ton 2 which is sidably mounted within the cylinder l. l

'llhe piston 2 serves as a reservoir for the Huid under pressure bywhich the jack is operated, the said piston being shown as hollow information and `having at its inner end a conventional packing ring orcup 3 which forms a tight chamber between the inner end of the pistonand the cylinder. rl`he kouter end of the piston is closed in anysuitable manner as by means of the cap 4 which is provided with adepending flange 5 which overlaps the edge of the cylinder to preventdust or foreign matter from entering the cylinder.

A fluid conduit pipe 6 extends longitudinally 85 said nuts also servingwith a washer 7a to 90 secure the packing cup 3 to the inner end of thepiston. rl`he outer end of the pipe 6 projects through the cover 4 andhas threaded thereon a cap 8 which closes the outer end of the pipe 6and serves in conjunction with 95 a clamping nut 9 to secure thecover-4c to the outer end of the piston 2, the said clamping nut 9 alsoserving with a washer 9a to secure a packing cup l0 between the cover land the piston to provide a fluid tight joint. A 10o jack head 11 issecured to the Y cap 8 in an)T suitable manner as by a thread connectionas shown by Figure l of the drawings, the said jack head serving as abearing surface for the axle of a vehicle. lt will be obvious that icathe manner of closing the outer end of the piston 2 may be varied asdesired, the present construction being only illustrative of onepossible construction for this purpose.

The piston 2 is charged with fluid under il@ pressure through an inletand valve nipple 13 which lhas one end thereof t-hreaded into the cap Sand through the side of the pipe 6, the said nipple being provided witha passage 11 opening through the outer end thereof and controlled by aconventional inwardly opening check valve 15. This valve 15 may be ofany suitable construction, but in the present instance is shown ascomprising a conventional tire-inflating valve 16 normally held againstits seat by a spring 1T and having an outwardly projecting stein 18. Atubular duct 19 is threaded through the cover l of the piston into thesaid passage 1l in the valve nipple 13. and when the inlet valve 15 isconnected to a compressed Huid supply the fluid is conducted through thepassage 11 and bushing 19 into the piston reservoir Q. 'hen it isdesired to use the j ack for jacking up a vehicle. the compressed uid inthe piston :2 is conveyed to the chamber 1:2 behind the piston through apassage :20 communicating with the passage 1l and the pipe 6. the saidpassage 20 being controlled by an inwardly opening check valve 21similar in construction to ythe valve 15. The valve :21 is provided withafinger button :22 for opening the valve. and when the said button ispushed inwardly the valve 21 is opened to allow the compressed fluid topass from the piston :2 into the chamber 12 as above described. When thecompressed Huid is thus conveyed into the chamber 12 the piston 2 israised thereby as indicated in Figure 2 of the drawings to jack up thevehicle in the usual way. In order to allow the piston 2 to resume itsnormal position and lower the vehicle. the compressed uid lin thechamber 12 is permitted to escape into the atmosphere through the pipe6. passage 2t" and a third inwardly opening check valve .73 incommunication with the passage 2U. the said check valve 23 being openedb v pressure upon the finger button Q-l thereof.

The capacity of the piston reservoir Q is preferably such as to containsutiicient fluid under pressure to operate the jack severalA times. andit will be seen that this is possible through Vthe very slight movementof the piston during its operation. It will also be seen that by reasonof the peculiar valve arrangement the piston reservoir can be easilycharged bv the attachment of any suitable source of compressed Huid tothe inlet valve 15 without effecting any movement of the piston withinthe cylinder. lTi'hen it is desired to jack up a vehicle it 1s merelynecessary to place the jack beneath the axle of the vehicle. press thefinger button 22 of the valve '21 to-open the same thus allowingsuiicient fluid to enter the chamber 1Q to raise the piston and elevatethe vehicle. and when it is desired to lower the vehicle it is merelynecessarv to press the linger button Q1 ofthe outlet valve 23 to allowthe Huid to escape from the cham ber 12. Owing to the comparativelysmall passage 2O the escape of the Huid will be comparatively slow so asto gradually lower the vehicle without jerks or jars upon the same. Thecompressed fluid supply is thus always carried by and within the jackitself so that it is unnecessary to use a hand pump or a,motor operatedpump to elevate the piston each time it is desired to use the jack, asis the usual practice with the modern types of pneumatic jacks).

When the jack is to be used in connection with a vehicle the axle ofwhich is a considerable distance above the ljack head 11 when the piston2 is in its lowermo'st position, a j ack head extension 25 may bepivotally secured to the jack head 11 as shown in Figure 5 of thedrawings so as to be swung into operative position upon the top of thejack head as shown in solid lines or thrown into inoperative position asshown in dotted lines. In the present instance this jack! head extension25 is shown as formed of a single strip of metal bent into the desiredform and having one yend thereof pivotally connected at 26 to anextension QT on one end of the jack head 1l, the other end of the stripbeing returned against the first-mentioned end and resting upon the jackhead 11. This extension 25 is particularly desirable in a jack of thistype where an unnecessarily long movement of the piston 2 would wastethe compressed fluid and reduce the number of times which the jack couldbe operated by one charging of the piston reservoir 2.

While I have shown and described one possible embodiment of myinvention, it will be obvious that many modications and changes can bemade in the construction thereof without departing from the spirit orscope of the invention. and I do not desire to be limited in theconstruction and use of my invention except as required by the followingclaims when construed in the light of the prior art..

Having thus described the invention. what- I claim is:

l. In a lifting jack. the combination of a, cylinder having a reservoirfor Huid under pre'ure within itself. a piston adapted to be operated bysaid fluid, a nipple secured upon said reservoir and having a mainpassage one end of which communicates with the cylinder behind saidpiston and the other end of which is adapted to be connected to a Huidpressure supply. said main passage also communicating intermediate itsends with a passage leading to said reservoir. a valve in said mainpassage between said last mentioned passage and the said cylinder behindsaid piston to permit Huid pressure from said reservoir to enter saidcylinder to operate said piston, and asecond valve for perfio,

mitting the eXhaust of said fluid pressure from said cylinder.

2. lin a lifting jack, the combination of a cylinder having a reservoirfor fluid under pressure within itself, a piston adapted to be operatedby said fluid, a nipple secured upon said reservoir and having a mainpassage one end of which communicates with the cylinder behind saidpiston and the other end of which is adapted to be connected to a fluidpressure supply, said main passage also communicating intermediate itsends with a passage leading to said reservoir and have ing a by-passbetween'said last mentioned passage and said reservoir communicatingwith the atmosphere. a' valve-in said main" passage between said lastmentioned passage and the said cylinder behind said piston topermittluid pressure from said reservoir to enter said cylinder tooperate said piston,

and a second valve in said h'y-pass to release the tiuid pressure insaid cylinder into the atmosphere.

ln a lifting jack. the combination of a cylinder, a piston insaidcylinder and having a reservoir for fluid under pressure therein. aconduit extending through said reservoir and having one end thereofcommunicating with the cylinder behind the piston, a main passage oneend of -which communicates with the said conduit and the other end ofwhich is adapted to be connected to a fluid pressure supply. a valve forpreventing escape of fluid from said supply connection. a second passagecommunicating with said first mentioned passage and said reservoir, avalve in said first mentioned passage between said second mentionedpassage'and the said conduit to control the flow of iiuid pressure fromsaid reservoir into said conduit. and a valved outlet for the fluidpressure in said cylinder behind the piston.

i. ln a lifting jack. the combination of a cylinder, a piston in saidcylinder and having a reservoir for fluid 'under pressure therein, aconduit extending through said reservoir and having one end thereofcommunicating with the cylinder behind the piston. a main passage oneend of which communicates with the said conduit and the other end ofwhich is adapted to be connected to a huid pressure supply, a valve forpreventing escape of iuid from said supply connection, a second passagecommunicating with said firstmentioned passage and said reservoir. avalve in said first mentioned passage between said second mentionedpassage and the said conduit to control the flow of fluid pressure fromsaid reservoir into said conduit, a by-pass communicating with said mainpassage and the atmosphere between said conduit and said secondmentioned valve, and a third valve in `said by-passl for controlling theexhaust of the ltiid pressure in said cylinder into the atmosphere, 2

|5. "in a. device of the character described, the combination of acylinder having a reservoir for Huid. under pressure arranged withinitself. a piston in said cylinder adapted to be, operated by saidiiuid,said reservoir being normally out, of communication with said piston, anipple having a passage therein adapted to be connected to a fluidpressure supply, said passage being also adapted to communicate withsa-id reservoir and the atmosphere, an outwardly closing check valvepreventing escape of the fluid through said supply connection, a valvecontrolling communication between said reservoir and said cylinderbehind the piston, and a valve for permitting escape, of said iiuidbehind the piston through said passage into the at mosphere.

6. ln a lifting jack, the combination of a cylinder, a piston in saidcylinder and having a reservoir for fluid under pressure therein. saidpiston having an inner head. a cover on the outer end of said piston, apipe extending longitudinally through said piston and having its endsthreaded into said inner head and said cover, one end of said pipeprojecting beyond said cover, and

the other end opening into the cylinder behind said piston, a capthreaded on the outer end of said pipe to clamp the said cover on saidpiston, a nipple secured upon said cap and having a passagecommunicating between the said reservoir in the piston and said pipe, avalve cont-rolling said passage, and means for exhausting the Huidpressure in said cylindei into the air. i

JAMES B. BOSTWECK.

